The goal of the Children's Activity Trial of Cardiovascular Health (CATCH) is to design, implement, and evaluate intervention programs for upper elementary age students that modify risk- related behaviors for primary prevention of cardiovascular disease. This proposal is for Phase I of CATCH. The major aims of Phase I are to determine the intervention programs, methods of evaluation, setting, and costs for Phase II. The cardiovascular health intervention programs have as their behavioral objectives to reduce fat and sodium consumption, increase complex carbohydrate consumption, increase regular aerobic physical activity levels, and reduce the onset rates of smoking. The proposed study describes an intervention that reflects a total push for cardiovascular health for the pre-adolescent population in grades 4-6. Three elementary schools in three urban Minneapolis school districts will be randomly assigned to three levels of intervention: Control, School Curriculum and Parent Involvement, School Curriculum, Parent Involvement and Environmental Change programs. The proposed intervention programs share a common conceptual orientation, derived from social learning theory. School curricula (Hearty Heart, the Planet Strongheart News, Slice of Life, Minnesota Smoking Prevention Program), which have been developed and evaluated at Minnesota, will be implemented in two schools. Parent Involvement programs (the Home Team, Smoke-Free Family), innovative correspondence programs for children and parents, will also be implemented in two schools. The Environmental Change programs target the school cafeteria, smoking policies, physical education program, and also include the implementation of physical activity challenges and a student health promotion council. Evaluation methods are tested for feasibility, reliability, and validity in Phase I and include physiological, behavioral, psycho-social, and process evaluation measures. The implications of Phase I for full implementation and evaluation in 36 schools in Phase II are discussed.